Adjustable operating arm



June 14, 1966 w. J. RUSSELL 3,255,641

ADJUSTABLE OPERATING ARM Filed Aug. 2, 1965 2 Sheets-Sheet 1 INVE NTOR WILLIAM J. RUSS ELL Maw HIS ATTORNEYS June 14, 1966 w. .1. RUSSELL 3,255,641

ADJUSTABLE OPERATING ARM Filed Aug. 2, 1965 2 Sheets-Sheet 2 INVE NTOR WILLIAM J. RUSSELL Mq'M United States Patent 3,255,641 ADJUSTABLE OPERATING ARM William J. Russell, Malvern, Pa, assignor to Robertshaw Controls Company, Richmond, Va., a corporation of Delaware Filed Aug. 2, 1963, Ser. No. 299,618

14 Claims. (Cl. 74559) This invention relates to an improved operating arm mechanism as well as'to an improved method for adjusting such mechanism or the like.

It is well known that limit switches for machines or the like are each actuated by an operating arm mechanism which is adapted to be moved by a moving part of the machine until an operating shaft connected to the arm mechanism has been rotated the desired degree whereby the rotated shaft causes operation of the limit switch to terminate the movement of the moving member of the machinery.

It has been found that when such arm mechanism is being secured to the operating shaft of the limit switch construction or the like, the means securing the operating arm mechanism to the operating shaft does not provide an accurate means for adjusting the position of the arm mechanism relative to the operating shaft.

Therefore, manufacturers have been striving to provide a suitable vernier type of adjustment for the roller carrying part of the actuating arm mechanism which is independent of the means securing the arm mechanism to the operating shaft.

Accordingly, one feature of this invention is to provide an improved means for adjusting the actuated part of the operating arm mechanism relative to the operating shaft after the operating arm mechanism has been secured to the operating shaft of a limit switch construction or the like.

In particular, this invention provides means for adjusting the roller carrying end of the arm mechanism in an arcuate path having its center of curvature coinciding with the axis of rotation of the operating shaft whereby the length of the actuating arm remains the same distance from the operating shaft in any of its adjusted positions, the adjusting means of this invention providing a fine adjustment for the actuating arm structure.

Accordingly, it is an object of this invention to provide an improved operating arm mechanism or the like having one or more of the novel features set forth above or hereinafter shown or described.

Another object of this invention is to provide an improved method of adjusting such an arm mechanism or the like.

Other objects, uses and advantages of this invention are apparent from a reading of this description which proceeds with reference to the accompanying drawings forming a part thereof and wherein:

FIGURE 1 is a perspective view illustrating the improved operating arm mechanism of the invention interconnected to a conventional limit switch construction.

FIGURE 2 is an enlarged, fragmentary, cross-sectional view taken on line 22 of FIGURE 1.

FIGURE 3 is a front, partial cross-sectional view of the mechanism illustrated in FIGURE 2 and is taken on the line 33 thereof.

FIGURE 4 is an exploded perspective view illustrating the various parts of the operating arm mechanism of this invention.

While the various features of this invention are herein after described and illustrated as being particularly adaptable for operating a limit switch or the like, it is to be understood that the various features of this invention can be utilized singly or in any combination thereof to provide means for actuating other devices as desired.

3,255,641 Patented June 14, 1966 ings are merely utilized to illustrate one of the wide variety of uses of this invention.

Referring now to FIGURE construction of this invention is generally indicated by the reference numeral 10 and comprises a'limit switch housing 11 containing a suitable limit switch to be operated in a desired manner upon the proper rotational movement of an operating shaft 12 rotatably disposed in the housing 11, the operating shaft 12 operating the limit switch structure in a conventional manner whereby the details thereof need not be disclosed as the same do not form a part of this invention.

However, the operating shaft 12 of the limit switch structure 10 is adapted to be rotated relative to the housing 11 to operate the limit switch by means of an operating arm mechanism 13 of this invention, the mechanism 13 comprising an arm base member 14 detachably secured to the operating shaft 12 in a manner hereinafter Thus, it can be seen that the limit switch construction I 10 of this invention is adapted to control the movement of a moving part of an apparatus or the like.

As previously set forth, it has been found that the means normally utilized to secure the operating arm mechanism 13 to the operating shaft 12 in a manner hereinafter described is not readily adaptable to permit a fine adjustment of the roller 16 relative to the operating shaft 12 for a particular application of the limit switch construction 10.

However, according to the teachings of this invention, means are provided for providing a fine adjustment of the actuating arm member 15 relative to the arm base member 14 of the actuating structure 13 in a unique manner whereby the roller 16 is adapted to be adjusted in an arcuate path about the axis of rotation of the operating shaft 12 whereby the distance of the roller 16 from the operating shaft 12 remains the same regardless of the adjusted position of the roller 16 relative to the operating shaft 12, a feature heretofore unattainable in limit switch actuating arm structure.

The particular details of the actuating mechanism 13 of this invention will now be. described and reference is made to FIGURES 2-4.

As illustrated in FIGURES 2-4, the arm base member 14 has a bore 18 passing transversely therethrough and adapted to telescopically receive the operating shaft 12 in the manner illustrated in FIGURE 2.

Another bore 19 passes through the arm base member 14 and is disposed transverse to the bore 18 while intersecting the same in an offset relation in the manner illustrated in FIGURES 2 and 3.

A fastening pin 20 is adapted to have the shank portion 21 thereof telescopically disposed in the bore 19, the his-- tening member 20 having an externally threaded end 22 adapted to project beyond the arm base member 14 for a purpose hereinafter described.

The shank portion 21 of the fastening member 20 is provided with a recess 23 which defines aflat cam surface 24 and a pair of opposed arcuate cam surfaces 25 in the manner illustrated in FIGURES 3 and 4.

1, an improved limit switch 7 An enlarged head 26 is provided on the other end of the fastening member and can be externally knurled or the like in the manner illustrated in FIGURE 3 to permit an operator to readily grasp the fastening member 20 and rotate the same relative to the arm base member 14 for a purpose hereinafter described.

When it is desired to assemble the arm base member 14 to the operating shaft 12, the fastening member 20 is disposed in the bore 19 in such a manner that the recess 23 permits the operating shaft 12 to be fully received in the bore 18 of the arm base member 14.

Thereafter, the fastening member 20 can be rotated rela-, tive to the arm base member 14 by the enlarged head 26 thereof until the flat cam surface 24 of the fastening member 20 engages the operating shaft 12 and tends to force the same upwardly in FIGURE 3 against the arm base member 14 whereby the arm base member 14 will be held by friction to the operating shaft 12.

A nut 27 is then tightened on the threaded end 22 of the fastening member 20 to draw the fastening member 20 to the right in the manner illustrated in FIGURE 3 whereby the left-hand arcuate portion 25 of the recess 23 further cams the operating shaft 12 upwardly into frictional engagement with the arm base member 14 whereby not only is the fastening member 20 held in its desired rotational position by the nut 27 compacting against the right side of the arm base member 14, but also the operating shaft 12 is secured to the arm base member 14 whereby rotational movement of the arm base member 14 in the manner previously described causes like rotation of the operating shaft 12 to operate the limit switch mechanism in the housing 11 in the manner previously described, a

The arm base member 14 has an arcuate slot 28 passing through the upper end thereof in the manner illustrated in FIGURE 4, the arcuate slot 28 being disposed on a radius of curvature extending from the axis of rotation of the operating shaft 12 when the operating shaft 12 is disposed in the bore 18 in the manner previously described.

A rear flange or tongue 29 extends downwardly from the arm base member 14 at a recess 30 provided therein, the recess 30 defining an arcuate portion 31 of the arm base member 14.

The actuating arm member 15 has a transverse bore 32 passing therethrough to also telescopically receive the operating shaft 12 in the manner illustrated in FIG- URE 2, the operating shaft 12 being loosely received in the bore 32 to permit the actuating arm member 15 to be movable relative to the shaft 12 even though the arm base member 14 is secured thereto by the fastening member 20 in the manner previously described.

The actuating arm member 15 has a forwardly extending arcuate flange 33 having a lower concave surface 34 complementary to the arcuate portion 31 of the arm base member 14 and an opposed convex surface 35 having a radius of curvature extending from the axis of the rotation of the operating shaft 12 for a purpose which will be apparent hereinafter.

The convex surface 35 of the flange 33 of the actuating arm member 15 is provided with a plurality of tooth means or half threads 36 for a purpose hereinafter described.

A groove means 37 is defined between the arcuate flange 33 of the operating member 15 and the remainder thereof and is adapted to interlockingly receive the tongue 29 of the arm base member 14 in the manner llustrated in FIGURE 2 to interlock the members 14 and 15 together while still permitting the member 15 .o be rotationally moved relative to the member 14 in he manner hereinafter described.

The actuating arm member 15 has a threaded bore 38 iassing therethrough and adapted to be aligned with the ircuate slot 28 in the arm member 14 when the members 14 and 15 are assembled together in the manner illustrated in FIGURE 2.

In this manner, a fastening member 39 is adapted to have the shank portion 40 thereof pass through the arcuate slot'28 and be threadedly received in the threaded bore 38 of the arm member 15 whereby when the enlarged head 41 of the fastening member 39 is tightened against the arm base member 14 in the manner illustrated in FIGURE 2, the arm base member 14 and actuating arm member 15 are frictionally held together in fixed positions relative to each other so that movement of the free end 17 of the actuating arm 15 causes the operating shaft 12 to rotate in unison therewith.

However, when the fastening member 39 is loosened, the operating arm member 15 is adapted to be moved about the axis of rotation of the operating shaft 12 relative to the arm member 14 within the limits of the fastening member 39 being moved in the arcuate slot 28 of the member 14 to permit the free end 17 of the actuating arm member 15 to be adjusted relative to the operating shaft 12 even though the arm base member 14 is secured from movement relative to the operating shaft 12.

The means for providing fine adjustment of the operating arm member 15 relative to the arm base member 14 when the fastening member 39 has been loosened in the above manner will now be described.

A threaded adjusting member 42 is adapted to be disposed on a cavity 43 defined between the cooperating portions of the interlocking flange 29 of the arm base member 14 and the flange 33 of the actuating arm member 15 in the manner illustrated in FIGURES 2 and 3 whereby the external threads 44 of the adjusting member 42 are adapted to be disposed in driving relation with the tooth means 36 on the flange 33 of the operating arm member 15.

The adjusting member 42 has an enlarged head 45 adapted to be compacted against the right sides of the member 14 in the manner illustrated in FIGURE 3 and has a reduced end portion 46 provided with an annular groove 47 to receive a C-ring 48. In this manner, a compression spring 49 is adapted to be disposed on the reduced portion 46 between the C-ring 48 and a suitable washer 50 which will be compacted against the left side of the member 14 in the manner illustrated in FIGURE 3 whereby the fastening member 42 is held in the cavity 43 of the members 14 and 15 in the manner illustrated in FIGURE 3.

In order to maintain driving relation between the teeth 44 of the adjusting member 42 and the teeth 36 of the flange 33 of the member 15, a bowed leaf spring 51 or the like is disposed in the cavity 43 between the member 14 and the fastening member 42 to urge the fastening member 42 down into driving relation with the teeth 36 of the flange 33 of the operating member 15 in the manner illustrated in FIGURES 2 and 3.

Thus, it can be seen that when the fastening member 39 is loosened in the arcuate slot 28 of the arm base member 14, the adjusting member 42 can be rotated in the proper direction by inserting a screwdriver or the like into the bifurcated enlarged head 45 of the adjusting member 42 so that rotation of the adjusting member 42 will cause the teeth 44 thereof to drive against the teeth 36 of the flange 33 of the operating member 15 and cause arcuate movement of the free end 17 of the operating member 15 about an arcuate path 52, FIG- URE 3, which has a radius of curvature extending from the axis of rotation of the operating shaft 12 whereby the distance of the free end 17 of the operating arm 15 from the axis of rotation of the shaft 12 remains the same in any of the adjusted positions of the arm member 15 relative to the shaft 12 as well as relative to the arm base member 14.

After the arm member 15 has been disposed in its adjustedv position by the fine adjusting member 42 in the above manner, the fastening member 39 is again tightened to secure the members 14 and 15 together.

' The roller 16 is adapted to be rotatably mounted to the free end 17 of the operating arm member 15 by a suitable shaft means 53 in a conventional manner whereby the roller 16 is adapted to be engaged by a moving part of the machine or the like to cause rotation of the operating shaft 12 in the manner previously described.

Therefore, it can be seen that this invention provides an improved actuating arm mechanism for a limit switch construction or the like wherein the roller 16 thereof is adapted to be adjusted in an arcuate'path 52 relative to the, operating shaft 12 with no change in the radius arm length of the roller 16 regardless of the adjusted position of the roller 16 relative ,to the shaft 12.

Further, no special tools are required for making such adjustments.

In addition, the parts of the operating mechanism 13 of this invention are so designed that the same can be readily pressure cast for maximum economy in manufacture and the like.

Also, the clamping screw or member 39 of this invention is so located that the same optimizes its clamping force with respect to the pivot point of the operating end of the actuating arm member 15. v

Thus, it can be seen that this invention not only provides an improved actuating arm mechanism having many novel features, but also this invention provides an improved method for adjusting such an arm mechanism or the like.

While the form of the invention now preferred has been disclosed as required by the statutes, other forms may be used, all coming within the scope of the claims which follow.

What is claimed is:

1. In combination, an operating shaft, a first operating arm member secured to said shaft, a second operating arm member carried by said first member and causing rotation of said shaft when said second member is moved about the axis of rotation of said shaft, said second member being adjustable relative to said first member about an are having its center coinciding with the axis of rotation of said shaft whereby the free end of said second member remains the same distance from said shaft in any of its adjusted positions, said first member having a groove therein, said second member having an L-shaped flange receivable in said groove to interlock said members together, and an adjusting means rotatably carried by said first member and disposed in said groove to cooperate with said flange to adjust said second member relative to said first member about said arc.

2. A combination as set forth in claim 1 wherein said first operating arm member is detachably secured to said shaft.

3. A combination asset forth in claim 1 wherein said free end of said second operating arm member carries a roller.

4. In combination, an operating shaft, a first operating arm member secured to said shaft, a second operating arm member carried by said first member and causing rotation of said shaft when said second member is moved about the axis of rotation of said shaft, said second member being adjustable relative to said first member about an are having its center coinciding with the axis of rotation of said shaft whereby the free end of said second member remains the same distance from said shaft in any of its adjusted positions, said first member having a groove therein, said second member having an L-shaped flange receivable in said groove to interlock said members together, an adjusting means rotatably carried by said first member and disposed in said groove to cooperate with said flange to adjust said second first member about said are, and means for locking said members in a selected adjusted position thereof.

5. A combination as set forth in claim 4 wherein said member relative to said 6 locking means includes a slot in said first member and a threaded fastening member carried by said second member and passing through said slot whereby tightening of said fastening member causes an enlarged head thereof to be drawn against said first member to lock said second member from movement relative to said first member.

6. A combination as set forth in claim 5 wherein said slot is arcuate and has a radius of curvature extending from said axis of rotation of said shaft.

7. A combination as set forth in claim 5 wherein said slot limits the degree of adjustment of said second member relative to said first member.

'8. In combination, an operating shaft, a first operating arm member secured to said shaft, a second operating arm member carried by said first member and causing rotation of said shaft when said second member is moved about the axis of rotation of said shaft, said second member being adjustable relative to said first member about an arc having its center coinciding with the axis of rotation of said shaft whereby the free end of said second member remains the same distance from said shaft in any of its adjusted positions, said members being interlocked together while being relatively movable, said first member having a groove therein, said second member having an L-shaped flange receivable in said groove to interlock said members together, and an adjusting means rotatably carried by said first member and disposed in said groove to cooperate with said flange to adjust said second member relative to said first member about said are.

9. A combination as set forth in claim 8 wherein said flange is arcuate and said groove is complementary to said arcuate flange.

10. In combination, an operating shaft, a first operating arm member secured to said shaft, a second operating arm member carried by said first member and causing rotation of said shaft when said second member is moved about the axis of rotation of said shaft, said second member having one end thereof provided with a bore telescopically receiving said shaft and being adjustable relative to said first member about an arc having its center coinciding with the axis of rotation of said shaft whereby the other end of said second member remains the same distance from said shaft in any of its adjusted positions, said first member having a groove therein, said second member having an L-shaped flange receivable in said groove to interlock said members together, and an ad justing means rotatably carried by said first member and disposed in said groove to cooperate with said flange to adjust said second member relative to said first member about said are.

11. In combination, an operating shaft, a first operating arm member secured to said shaft, a second operating arm member carried by said first member and cans-ing rotation of said shaft when said second member is moved about the axis of rotation of said shaft, said first member having a groove therein, said second member being provided with an arcuate L-shaped flange portion having a center of curvature coinciding with said axis of rotation of said shaft and having teeth means thereon, said flange being received in said groove, and a threaded adjusting member rotatably carried by said first member and disposed in meshing relation with said teeth means to cause adjustment of said second member relative to said first member about the axis of rotation of said shaft when said threaded member is rotated whereby the free end of said second member remains the same distance from said shaft in any of its adjusted positions.

12. A combination as set forth in claim 11 wherein biasing means holds-said threaded member in engagement with said teeth means.

13. A combination as set forth in claim 11 wherein biasing means holds said threaded member to said first member.

14. A combination as set forth in claim 11 wherein said first and second members cooperate together to de- References Cited by the Examiner UNITED STATES PATENTS 664,578 12/1900 Pancoast 74599 X 1,055,398 3/1913 Horvath. 1,088,247 2/1914 Thompson 74-559 X 1,421,408 7/1922 Collyer 28752.02 1,475,257 11/1923 Bottone.

8 Harry et a1. 74-559 X Mitchell 287-44 X Spicacci 1 287-5208 X McLean 287-52.08 X Brin.

'Dehn 74-559 Kiessling 74548 X BROUGHTON G. DURHAM, Primary Examiner. l C. F. GREEN, Assistant Examiner. 

1. IN COMBINATION, AN OPERATING SHAFT, A FIRST OPERATING ARM MEMBER SECURED TO SAID SHAFT, A SECOND OPERATING ARM MEMBER CARRIED BY SAID FIRST MEMBER AND CAUSING ROTATION OF SAID SHAFT WHEN SAID SECOND MEMBER IS MOVED ABOUT THE AXIS OF ROTATION OF SAID SHAFT, SAID SECOND MEMBER BEING ADJUSTABLE RELATIVE TO SAID FIRST MEMBER ABOUT AN ARCH HAVING ITS CENTER COINCIDING WITH THE AXIS OF ROTATION OF SAID SHAFT WHEREBY THE FREE END OF SAID SECOND MEMBER REMAINS THE SAME DISTANCE FROM SAID SHAFT IN ANY OF ITS ADJUSTED POSITIONS, SAID FIRST MEMBER HAVING A 